A planetary gear train of an automatic transmission may include an input shaft, an output gear, a first planetary gear set always outputting a negative rotation speed from a rotation speed input from the input shaft, a second planetary gear outputting the negative rotation speed input from the first planetary gear set or converting negative rotation speed into a positive rotation speed and outputting the positive rotation speed, a compound planetary gear set formed by third and fourth planetary gear sets and changing the rotation speed selectively through two paths and into nine forward speeds and one reverse speed, eight rotational members including two rotation elements connected to each other or one rotation element among the rotation elements of the first and second planetary gear sets and the compound planetary gear set, and a six friction members, and a transmission housing.